Our investigations centered on the evaluation of bone marrow from patients with plasma cell cancers. Normal plasma cells (PC) produce immunoglobulins (antibodies), useful proteins that help fighting infections. When PC become cancerous they may cause serious diseases. The typical example is multiple myeloma (MM), a currently incurable cancer that destroys bones, impairs blood cell formation in the marrow, decreases immunity and may damage kidneys and nerves. The severity of the disease largely depends on the amount of tumor within the bone marrow. MM and its precursors such as smoldering myeloma are currently studied in detail and new treatments are being investigated intensely. Our role in these investigations was to examine bone marrows from patients with MM and related disorders utilizing state-of- the-art laboratory techniques to determine the number and distribution of PC within the marrow and characterize their nature. These observations are then correlated with other laboratory and clinical data to determine the clinical behavior of these cancers and their response to therapy. Another collaborative study consisted on examining cultured red cells obtained from children with sickle cell disease (SCD), a serious genetic disorder of red cells that make them change shape and become more fragile. The clinical outcomes and response to current therapy among patients with SCD vary widely and new treatments are badly needed. After taking circulating progenitor cells (called CD34+ cells) from these patients and inserting a gene coding for a protein designated as LIN28A, we observed in cultures that the descendant red cells from the CD34+ cells were less frequently sickle cells in comparison to the controls. Further studies using this or a similar approach may contribute to develop effective therapies for SCD.